Adjusting device for throttle valves



United States Patent 3,502,000 ADJUSTING DEVICE FOR THROTTLE VALVESChristoph Heinrich Voges, 14 Algermissen Markt Str. 3201, Algermissenuber Hildesheim, Germany, and Gerd Johren, Kurt Schumacher Ring 29,Wolfsburg 318, Germany Filed Mar. 10, 1967, Ser. No. 622,230 Claimspriority, application Germany, Mar. 11, 1966, 1,526,548 Int. Cl. Fb13/042, 11/10; F0211 11/08 U.S. Cl. 91-47 1 Claim ABSTRACT OF THEDISCLOSURE An adjusting device for the throttle valves for thecarburetors of internal combustion engines operating in dependence onthe underpressure of the suction pipe to the engine and effectiveindependently of the altitude of the motor vehicle.

This invention relates to an adjusting device for throttle valvesoperating in dependence on the underpressure of the suction pipe of theengine of a motor vehicle. The fluctuation of the underpressure is dueto changes in air pressure when altitude changes.

Pneumatic dashpots have been known which delay the return of thethrottle into the closing position (idling position) by the fact that anarm of the control lever of the throttle valves will encounter a pestleor rammer of the dashpot shortly before the closing position of thethrottle valve. The pestle, at the same time, must shift a membraneclamped in the housing and it must drive out the air through a narrowopening from one of the housing chambers. In this manner it is to beavoided that the motor stops at a sudden release of the gas pedal.

Furthermore, devices of a similar mechanical construction have beenknown where the membrane is controlled in dependence on theunderpressure. At the same time, beginning with a sudden underpressure,a limit is to be set for the movement of the throttle valve. In thismanner, the poisonous or objectionable part of the exhaust gas can belowered or decreased. In these devices, also, provision has been made,as a rule, that a closing of the throttle valve at a sudden release ofthe gas pedal will take place in a delayed manner despite the thensudden reduction of the underpressure.

The present invention is based on the realization that the underpressureadduced for control purposes is to a large extent dependent on theatmospheric pressure and that, in this manner, the controlcharacteristic of the adjusting device will depend on the altitude atwhich the vehicle is used. As is well known, the atmospheric pressuredrops with an increasing altitude of the locality and, in proportionwith that, the absolute pressure of the suction pipe, correspondingly,the difference of these two pressures, the underpressure of the suctionpipe, is then also changed. If the atmospheric pressure, for example,drops from 1.0 to 0.8 atmosphere, then the underpressure of the suctionpipe decreases, for example, from 0.5 to 0.4 atmosphere. Therefore, anadjusting device balanced as to the low plains then becomes ineffectivein the case of travel in high mountains. Vice versa, the closingmovement of the throttle valve of a device adjusted in the mountainswould be limited in an undesirably pronounced manner in the case oftravel in the low plains, so that the underpressure of the suction pipewould keep the throttle valve open even during idling or increase of theidling speed.

In order, therefore, to allow the adjusting device to become eifectiveindependently of the altitude of the locality, the proposal is made thatthe change of the underpressure, which is effective for the control, becompensated automatically in dependence on the atmospheric pressure withthe assistance of an evacuated spring-loaded diaphragm box that is ananeroid case.

Further objects of the invention will be apparent from the followingdescription when considered in connection with the accompanying drawingin which:

FIGURE 1 is a diagrammatic view showing the basic method of operation ofan adjusting device of a throttle valve, and

FIG. 2 is; a cross sectional view of an adjusting device of a throttlevalve with a pressure casing according to the invention connectedthereon.

FIG. 1 shows the discharge part of a carburetor 1, with the throttle orbutterfly valve 2 indicated, shown in a dashed line. The throttle valveis connected with an adjusting lever 3 which can be adjusted in a knownmanner by means of a Bowden cable 4 by the gas pedal which has not beenshown. The normal idling position of the throttle valve 2 is determinedby an adjustable stop screw 5, which can be screwed into an arm 3a ofthe adjusting lever 3 of the throttle valve and which cooperates with astop 6 on the carburetor housing. The second arm 3b of the levercooperates with a two-armed lever 7, one of the arms of which havingbeen articulated to the pestle or rod 8 of a diaphragm device 9, theconstruction of which will be explained in connection with FIG. 2.

The adjusting device, attached to a cross member or right-angle arm 10of the carburetor 1, has a housing 11, that has been subdivided into twochambers 13 and 14 by a diaphragm 12. The diaphragm 12 has been fixedlyconnected with the already described pestle or rod 8. When the engine isturned oil, the diaphragm 12 is pressed by a spiral spring 15 into theleft-hand final position shown in FIG. 2, as a result of which the rod8, FIG. 1, is pushed into its right-hand final position, and, as aresult thereof, the closing movement of the throttle valve 2 is notlimited. The chamber 14 can be connected by a valve 16 with a chamber17, which is in constant connection by a tube 18 with the suction pipeof the engine which latter is not shown. The chamber 17 has been closedon one side by a diaphragm 19, to which the valve body 16 has beenattached. Normally, the diaphragm 19 is pressed into its right-hand endposition by a spring 24, and in the case of underpressure in the suctionpipe, it is made to bulge out toward the left, counter to the effect ofthe spring 24, and, in doing so, it will open the valve 16. As a resultthereof, an underpressure will also build up in the chamber 14 and thediaphragm 12 is pressed toward the right, counter to the effect of thespiral spring 15, since the air of the atmosphere can flow into thechamber 13 through the annular opening 21. At the same time, the stopfor the adjusting lever 3 of the throttle valve becomes efiective. Inthe valve body 16, an opening 25 of a small diameter, has been providedthrough which air continuously flows into the chamber 14. This increasein pressure in the chamber 14 is only partially reduced by the openedvalve 16, because the valve acts as a flow throttle, as a result ofwhich the underpressure in chamber 14 becomes less than in the chamber17. In the case of a sudden drop in the underpressure in the suctionpipe, as a result thereof the valve 16 will, first of all, be closed,whereupon the underpressure in the chamber 14 is reduced only graduallyby means of the opening 25. In the case of a sudden release of the gaspedal, therefore, the throttle valve 2 will reach its closed position ina delayed manner.

The description of the adjusting device for the throttle valve, asdescribed, corresponds to the status of the prior art. As described inthe introduction, the underpressure of the suction pipe, fluctuatingwith the altitude of the locality in which the vehicle travels, wouldhowever make the etficiency of the device strongly dependent on thealtitude. According to the invention, therefore, an additional evacuatedspring-loaded diaphragm case (aneroid box) 22 has been provided, whichexerts a force on the control valve 16 which is dependent on thedropping atmospheric pressure, which force corresponds to the force thatis lacking on the membrane 19 in the case of a dropping underpressure ofthe suction pipe.

This force increases in the case of a dropping atmospheric pressure inthe same measure in which the force on the control diaphragm decreasesbecause of the simultaneously decreasing underpressure in the suctionpipe.

The sum of forces from the aneroid case 22 and the control diaphragm 19remains constant in any atmospheric pressures, so that the adjustingdevice will respond independently of altitude.

The adjustment of the point of response of the adjusting device ispossible with the aid of the adjusting screw 23, by which an adjustingspring 24 below the control diaphragm 19 and the diaphragm case 22 canbe tightened in relation to one another.

We claim:

1. Throttle valve closure limiter for internal combustion enginescomprising a diaphragm chamber consisting of a housing and a diaphragmthe outer side of which is exposed to atmospheric pressure, an adjustingmember connected to the diaphragm and arranged on the outer sidethereof, a second diaphragm chamber consisting also of a housing and adiaphragm with the housing having means to connect the chamber to asuction pipe of the engine and the outer side of the diaphragm beingexposed to atmospheric pressure, springs Within both diaphragm chambersto press the diaphragms outwardly, a valve provided between the twodiaphragm chambers and connected to the second diaphragm and arranged onthe inner side thereof, a shaft of the valve penetrating the seconddiaphragm and having an outlet opening of small diameter on the outerside of the second diaphragm, and in communication with thefirst-mentioned diaphragm chamber, a spring, an evacuated case connectedto the outer side of the second-mentioned diaphragm urged by thelastmentioned spring, and setting means for adjusting the pressure ofthe last mentioned'spring.

References Cited UNITED STATES PATENTS 1,978,862 10/1934 Gregg 91473,027,884 4/1962 Bale et a1 123117.1 3,169,513 2/ 1965 Hennequin 91473,266,473 8/1966 Rhodes 123l03 3,355,992 12/1967 Jacobson et al. 91472,205,354 6/1940 Gregg et a1. 123119 PAUL E. MASLOUSKY, Primary ExaminerUS. Cl. X.R. 91468; 123103

